A conventional pharmaceutical injection device comprised a main body case that had an injection needle insertion and retraction opening, a pharmaceutical syringe mounting portion provided within this main body case, a piston provided movably with respect to a pharmaceutical syringe that was mounted to this pharmaceutical syringe mounting portion, a drive mechanism for driving this piston, a controller that was electrically connected to this drive mechanism, and a display section that was electrically connected to this controller (see Patent Literature 1, for example).